High-definition surveillance has high-definition, high-level, high-resolution and other features. It can also guarantee dynamic image quality in a variety of low-light environments. With intelligent video analysis and automatic recognition capabilities, it can achieve high-quality security monitoring equipment, but In the case of high demand, what are the requirements for the quality of the lens of the monitoring equipment? The following is a discussion of the lens used in security HD surveillance systems from these two aspects.
The optical performance of the lens appear <br> <br> high-definition cameras to image quality security system brought a significant upgrade. Such as 720p, 1080p IP high-definition camera, 3M, 5M resolution industrial high-definition cameras. The accompanying high-definition lenses also mushroomed in the market. However, after the actual use, a lot of problems have been discovered, and so are the mixed forces. There are high resolution resolutions at ordinary resolution, non-uniform resolution, resolution of the center portion of the lens, poor edge resolution, etc., and the actual application is not optimistic.
For security systems, especially road monitoring applications, the lens is required to have high resolution in the full range of viewing angles (such as with the 1080p HD camcorder, the lens resolution requirements of 2M or more), in simple terms, is the lens MTF graphs have higher requirements. At the same time, in order to fully reflect the low illumination characteristics of the camera, the lens should have a large amount of light (the F value should be small).
â— MTF value of the lens The MTF value of the lens can be used to analyze the image quality of a lens. The MTF value (modulus transfer function) is a numerical value that comprehensively evaluates the sharpness, contrast, and resolution of the lens. Of course, the MTF value of the lens is not omnipotent. It does not show the color difference, dispersion, field curvature, etc. of the lens. Therefore, it cannot describe everything of the lens, but it is indeed the most scientific and most comprehensive indicator of the optical power of the lens at this stage.
â— Lens Aperture Value The aperture factor F value is the reciprocal of the relative aperture, and the relative aperture is the relative value of the lens pass-through diameter divided by the focal length of the lens. The F value is an important reference index for measuring the amount of light passing through the lens. The smaller the aperture coefficient F, the more light will enter the same unit time.
In the general monitoring system, especially the road monitoring system, the illumination of the whole day changes greatly. Before ensuring the better image quality in the F8 aperture of the lens, the lens used for long-distance monitoring at night requires sufficient F-values. Small, to ensure good imaging quality in larger relative caliber conditions. Of course, the smaller the value of F, the more expensive the lens, such as the zoom lens of a large multiple, the lens price is much higher than the price of the other parts of the camera. In addition to the aperture value of the lens, the day and night lens used in the road monitoring system, especially the urban road monitoring, must also take into account the infrared light correction under the lighting conditions to ensure the clarity of the image.
The outdoor monitoring system generally requires the use of an automatic iris lens due to the large variation in light. Of course, the actual amount of light through the lens, in addition to the F value is also related to other factors, such as the coating, the lens material and the size of the lens itself. We have found the same F value in the test, the actual amount of light will be a difference of 20%.
The optical performance of the above lens and the special requirements of the monitoring system require that the MTF of the lens be of high quality under a relatively large aperture, and the high-definition lens that can faithfully represent the performance of a high-definition camera has a very high selection of materials and manufacturing processes. Claim.
According to the overall cost performance of the lens on the market, we suggest that the F value of the manual zoom lens is 1.2 to 1.4, and the F value of the power zoom lens is 1.6 to 1.8. In order to maximize the camera's low-light performance.
Application Engineering <br> <br> HD monitoring system performance HD lens, the lens not only have good optical performance, the good engineering performance (easy to debug, high stability) has highlighted its importance, otherwise the lens focus The inaccuracy of the image will degrade the image quality, and it will not reflect the advantages of high definition.
In view of this, we propose that in the HD system, manual zoom lenses that are mostly used for fixed monitoring points should have the following engineering features:
Multi-phase focus point: There is only one focus point for the traditional manual zoom lens, which is very difficult to grasp in the HD system, especially the outdoor adjustment. The multi-phase focus point ensures accurate commissioning and ensures high-definition quality.
Change focus function: After the focus of the lens is finished, adjusting the focal length of the lens can still keep the image clear until the required focal length.
With the development of high-definition surveillance becoming more and more obvious, security industry technology slowly matures. In addition to the improvement of optical performance of high-definition lenses, the production and assembly of the lens also changes. Today, megapixel lenses face two major problems: First, the manufacturing process, processing precision and other aspects are higher than the ordinary lens; Second, in the field of monitoring high-definition, many products such as transmission equipment, display equipment, The high-definition of video equipment, bandwidth, etc. is not ideal. In the face of such challenges, it is still difficult for a million HD surveillance cameras to truly achieve popularity. However, there are indications that the day of the emergence of millions of high-definition lenses will not be too long, in the next 3-5 years, HD surveillance cameras will have an ideal market response.
The optical performance of the lens appear <br> <br> high-definition cameras to image quality security system brought a significant upgrade. Such as 720p, 1080p IP high-definition camera, 3M, 5M resolution industrial high-definition cameras. The accompanying high-definition lenses also mushroomed in the market. However, after the actual use, a lot of problems have been discovered, and so are the mixed forces. There are high resolution resolutions at ordinary resolution, non-uniform resolution, resolution of the center portion of the lens, poor edge resolution, etc., and the actual application is not optimistic.
For security systems, especially road monitoring applications, the lens is required to have high resolution in the full range of viewing angles (such as with the 1080p HD camcorder, the lens resolution requirements of 2M or more), in simple terms, is the lens MTF graphs have higher requirements. At the same time, in order to fully reflect the low illumination characteristics of the camera, the lens should have a large amount of light (the F value should be small).
â— MTF value of the lens The MTF value of the lens can be used to analyze the image quality of a lens. The MTF value (modulus transfer function) is a numerical value that comprehensively evaluates the sharpness, contrast, and resolution of the lens. Of course, the MTF value of the lens is not omnipotent. It does not show the color difference, dispersion, field curvature, etc. of the lens. Therefore, it cannot describe everything of the lens, but it is indeed the most scientific and most comprehensive indicator of the optical power of the lens at this stage.
â— Lens Aperture Value The aperture factor F value is the reciprocal of the relative aperture, and the relative aperture is the relative value of the lens pass-through diameter divided by the focal length of the lens. The F value is an important reference index for measuring the amount of light passing through the lens. The smaller the aperture coefficient F, the more light will enter the same unit time.
In the general monitoring system, especially the road monitoring system, the illumination of the whole day changes greatly. Before ensuring the better image quality in the F8 aperture of the lens, the lens used for long-distance monitoring at night requires sufficient F-values. Small, to ensure good imaging quality in larger relative caliber conditions. Of course, the smaller the value of F, the more expensive the lens, such as the zoom lens of a large multiple, the lens price is much higher than the price of the other parts of the camera. In addition to the aperture value of the lens, the day and night lens used in the road monitoring system, especially the urban road monitoring, must also take into account the infrared light correction under the lighting conditions to ensure the clarity of the image.
The outdoor monitoring system generally requires the use of an automatic iris lens due to the large variation in light. Of course, the actual amount of light through the lens, in addition to the F value is also related to other factors, such as the coating, the lens material and the size of the lens itself. We have found the same F value in the test, the actual amount of light will be a difference of 20%.
The optical performance of the above lens and the special requirements of the monitoring system require that the MTF of the lens be of high quality under a relatively large aperture, and the high-definition lens that can faithfully represent the performance of a high-definition camera has a very high selection of materials and manufacturing processes. Claim.
According to the overall cost performance of the lens on the market, we suggest that the F value of the manual zoom lens is 1.2 to 1.4, and the F value of the power zoom lens is 1.6 to 1.8. In order to maximize the camera's low-light performance.
Application Engineering <br> <br> HD monitoring system performance HD lens, the lens not only have good optical performance, the good engineering performance (easy to debug, high stability) has highlighted its importance, otherwise the lens focus The inaccuracy of the image will degrade the image quality, and it will not reflect the advantages of high definition.
In view of this, we propose that in the HD system, manual zoom lenses that are mostly used for fixed monitoring points should have the following engineering features:
Multi-phase focus point: There is only one focus point for the traditional manual zoom lens, which is very difficult to grasp in the HD system, especially the outdoor adjustment. The multi-phase focus point ensures accurate commissioning and ensures high-definition quality.
Change focus function: After the focus of the lens is finished, adjusting the focal length of the lens can still keep the image clear until the required focal length.
With the development of high-definition surveillance becoming more and more obvious, security industry technology slowly matures. In addition to the improvement of optical performance of high-definition lenses, the production and assembly of the lens also changes. Today, megapixel lenses face two major problems: First, the manufacturing process, processing precision and other aspects are higher than the ordinary lens; Second, in the field of monitoring high-definition, many products such as transmission equipment, display equipment, The high-definition of video equipment, bandwidth, etc. is not ideal. In the face of such challenges, it is still difficult for a million HD surveillance cameras to truly achieve popularity. However, there are indications that the day of the emergence of millions of high-definition lenses will not be too long, in the next 3-5 years, HD surveillance cameras will have an ideal market response.
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Guangdong Fabia Intelligent Technology Co., Ltd , https://www.fabiaintelligent.com